Recently my Ercoupe's C-85 lost oil prime which resulted in no oil pressure on start-up. Unfortunately, it ran for around 15-minutes - including a run-up, before being noticed. Long story, it was a "friend" warming up plane for oil change and did not notice. I know, I know, the engine is ruined, right? Except, I want to add some details ... the operating temperature never got beyond the low end of the green arc. Then, after priming the oil pump, I re-started it and it ran and sounded great (did not fly yet). I then sent the oil in for an analysis, which showed iron, aluminum and tin a bit high ... but lab noted it is not unusual for an engine with under 100 hours (mine had 76 at the time). Since then I've changed the oil and filter to run some more before testing the oil again. I haven't flown it since the "incident". The engine starts immediately, runs great, no noises, no high temps, no unusual behavior. Conventional thought says the engine is shot ... but ... is that a 100% certainty?